3.1. Asymmetry in skull shape in dorsal and ventral view
analyses respectively
Procrustes ANOVA demonstrated (Table 1) that in both dorsal and ventral
view analyses the results are highly repeatable (F=10.5501 and 4.1967,
P=0.0001) for dorsal and ventral views respectively as between sides
variation values are larger than within sides variation (measurement
error) contributions (F=0.00034755 and 0.0024199, P= -) respectively in
the same order. FA accounted for 61.77% and 72.01% of variations in
dorsal and ventral cranium, respectively and was not found significant
(p˂0), signal noise for dorsal view was observed significantly high
(F=0.00034755) and comparable to values for FA (ns) and could not be
employed for further analysis.
A regression model of log transformed centroid size and asymmetric
components suggested the significant expression of asymmetry throughout
ontogeny (p˂0.03) and that size accounted for 81.34% of asymmetric
shape changes of this component. Further, a multivariate analysis of
regression confirmed DA and a low significance (p˂0.5) of fluctuating
asymmetry (FA) (F1539=3.4045, F882=
3.2665) for dorsal and ventral views (Table 2). More shape changes
concentrated collectively more on the rostro-dorsal and caudal areas and
were right side biased (Fig. 4a and b) suggestive of a low association
between environment and skull development in Small Pangolins to justify
observed skull asymmetries (hypothesis 1).
Intraspecific allometric ontogenetic trajectories among samples under
assessment suggested a rostro-caudal followed by a caudo-lateral growth
trajectory considering the intercepts for shape versus size predictions
(Fig. 5) was found parallel. Intercept (-4.43), slope (-11.168) p˂0.0004
while overall statistics R2= 0.013, Wilk’s
Lambda=1.07E-11, df-21, 7, F=3.091E 10, p˂0.0001. in a pooled sample
population across geographical locations.
Figure 4a, b and c Grid representation of PCA implied
deformation for directional asymmetry, (b) Implied deformation for
individual side interaction (FA) for dorsal skull views ( Mag X 10) (c)
Regression model of log transformed centroid size (CS) versus asymmetric
components of data in P. tricuspis